Imagine a situation in which variable y depends on variable x (for example, y might be profit and x the number of items sold). If y increases as x increases, how would this be indicated in a table? In a graph?
Ans- In this situation if y increases as x increases this would indicated on a table like this:
Variable x
0
1
2
3
4
5
Variable y
0
10
20
30
40
50
Like you can see on this table that variable x goes higher and higher by 1's while variable y goes higher and higher by 10's. So in this situation both y and x variables go higher or they increase. In a graph it would look something like this :
If variable y decreases as variable x increases (for example, y might be the amount of money in your wallet on a trip and x the time you have been traveling), how would this be indicated in a table? In a graph?
Ans- If y decreases as x increases the table would look like this:
Variable x
0
1
2
3
4
5
Variable y
0
-1
-2
-3
-4
-5
If y decreases as x increases and if the y axis starts with a 0 we would start getting negative numbers. The graph would look something like this:
In a coordinate graph of two related variables, when do the points lie in a straight line?
Ans- The points lie in a straight line when nothing is increasing or decreasing on the graph. This would not make sense if time was one of the variables because time can never stop. This will also show up when the x axis and y axis always stay the same.
In a coordinate graph of two related variables, when is it appropriate to connect the points?
Ans- It is appropriate to connect the points when the data is continues or keeps on going and never stops. One example of a continues data is time. It can never stop. Some people also predict the data plots.
Summary
Think about your answers to these questions, discuss your ideas with other students ad your teacher, and then write a summary of your findings in your journal.
The most important thing in this investigation was that when would the line of the data plots would be in a straight line and when would it be appropriate to connect the points on the graph.
15/9/2008
Mathematical Reflections Investigation 3
Imagine a situation in which variable y depends on variable x (for example, y might be profit and x the number of items sold). If y increases as x increases, how would this be indicated in a table? In a graph?
Ans- In this situation if y increases as x increases this would indicated on a table like this:
If variable y decreases as variable x increases (for example, y might be the amount of money in your wallet on a trip and x the time you have been traveling), how would this be indicated in a table? In a graph?
Ans- If y decreases as x increases the table would look like this:
In a coordinate graph of two related variables, when do the points lie in a straight line?
Ans- The points lie in a straight line when nothing is increasing or decreasing on the graph. This would not make sense if time was one of the variables because time can never stop. This will also show up when the x axis and y axis always stay the same.
In a coordinate graph of two related variables, when is it appropriate to connect the points?
Ans- It is appropriate to connect the points when the data is continues or keeps on going and never stops. One example of a continues data is time. It can never stop. Some people also predict the data plots.
Summary
Think about your answers to these questions, discuss your ideas with other students ad your teacher, and then write a summary of your findings in your journal.
The most important thing in this investigation was that when would the line of the data plots would be in a straight line and when would it be appropriate to connect the points on the graph.